It is known that living polybutadienyllithium end groups will remove a hydrogen from a primary or secondary amine and thus terminate the polymerization. (D.M. French; Rubber Chemistry Technology 42, 90 -- 1969.) Consequently, the formation of living polybutadiene in concert with primary or secondary (1.degree. and 2.degree.) amine functionally is prohibited. It has been shown that aniline substituted with N,N-trimethylsilyl groups is stable to organometallic reagents. (W. Broser, W. Harrer, Ang. Chem. I.E. 4, 1081 --1965.) According to this invention, polymers which are mono- or di- terminated with N,N-bis (trialkylsilyl) amino groups in which the alkyl group contains 1 to 8 carbon atoms, are prepared and are further converted to amino-terminated polymers.
N,N-bis (trialkylsilyl) amino- mono- and di- terminated polymers of the class consisting of (a) homopolymers of conjugated dienes containing 4 to 8 carbon atoms, (b) copolymers of such conjugated dienes and (c) copolymers of such a conjugated diene and a vinyl monomer, the alkyl groups of which contain 1 to 8 carbon atoms, are new as is the intermediate, (SiR.sub.3).sub.2 N--Ar--P--Li. Amino-terminated polybutadiene is mentioned on page 90 of D.M. French, supra. No disclosure of a compound of the formula H.sub.2 N--Ar--P--H, disclosed in the accompanying drawings, has been found in the art, and such compounds are claimed as new. In fact, a polymer derived from such a conjugated diene, with or without a vinyl monomer, with one or two or more --NH.sub.2 terminal groups, of the generally more valuable commercial type, i.e. anionically produced, is new and claimed herein. Amine-terminated polybutadiene polymers are useful precursors to polybutadiene-Nylon 6 block copolymers which are useful as high-impact resins. The products of this invention are also useful intermediates for this purpose and for the preparation of polydiolefin-polyurea, polydiolefin-epoxy resins, and other applications of amine-terminated polymers known to those skilled in the art.
POLYBUTADIENE-Nylon 6 block polymers are usually prepared through the intermediacy of isocyanate-terminated polymers. (W. L. Hergenrother, R. J. Ambrose, J. Polym. Sci. B, 10, 679; 1972.) The amine-terminated polymers such as those disclosed herein can also act as intermediates for polybutadiene-Nylon 6 di- and tri- block polymers. Furthermore, the amine polymers have stability and therefore can be stored and transported. This is an advantage over the isocyanate-terminated polymers. It is well known that amine groups are less sensitive to protic materials, such as moisture, alcohols, etc. than are isocyanate groups.
Amine-terminated polymers prepared according to Zelinski, Hseih and Stroble, U.S. Pat. No. 3,109,871, are terminally reactive but cannot be used in carrying out this invention because the end groups include an active hydroxyl, and the amine is tertiary in nature such as ##STR1##
According to the present invention, primary-amine-terminated polymers are prepared from which the block copolymers may be produced.